Welding SA213-T23 2

[fborela]

Hello
I have to weld tube-tube diameter 42.4 and thickness 4.5 mm quality SA213-T23.
I suppose that I need to Preheat > 150ºC.
Do I need to make PWHT, what holding Temperature? what time? I found searching in the web some papers. Any of them specified PWHT 740 ºC 2 hours, another specified PWHT is not necesary for smaller thickness. I am confused.
I cannot find information about this material in ASME I neither ASME IX.

Thank you in advance:
Fernando Sieiro

 

[metengr]

The use of this material is permitted per ASME B&PV Code Case 2199-6, and follows the welding requirements for P-No 5A base material. For ASME SA 213 T23, the preheat should be 400 deg F or 200 deg C.

For this material thickness, no PWHT is required.

 

[stanweld]

PWHT is not required per ASME I and the referenced Code Case. We preheat at 300 F minimum and have done extensive hardness testing in developing our procedures. We weld with "T23 matching" filler metals from either Bohler or Metrode. While there are those who claim welding can be done safely without PWHT and weld hardness will not exceed 350 BHN, we have definitely disproved that notion, recording hardness up to 365 BHN. Our as welded hardness on tubes range between 275 BHN to 325 BHN with the 300 F preheat. Stress corrosion cracking may occur at hardness values near to and above 350 BHN.

On heavy wall P23 pipe we use 400 F preheat.

 

[metengr]

We have used 400 deg F preheat even on thinner wall material with excellent success.

 

[stanweld]

Of the more than 10,000 T23 tube welds made in the field by the company and in operation for four to six years in coal fired power boilers, no cracking or leakage has been reported to date. We have also performed numerous hardness checks on the completed welds with the large majority having hardness less than 290 BHN, equivalent. I would never attempt to discourage higher preheat temperatures but I certainly would discourage lower or no minimum preheat.

 

[fborela]

Then I´ll make preheat at 200 ºC and PWHT at 735 ºC 1 hour. Is that well in your opinion?

 

[metengr]

For this tube wall thickness and elevated preheat, I really do not see the need for PWHT.

 

[stanweld]

There will be no need to PWHT with your selected preheat.